Replace variable_list with variables_dt throughout hts_summary_wrapper()

[ashleyasmus]

hts_summary_wrapper is grabbing the variable_list that is loaded automatically when the package loads (I don't like that this happens, see #167). Easy fix here, just replace variable_list with variables_dt:

travelSurveyTools/R/hts_summary_wrapper.R

Lines 119 to 133 in bf48868

	variables_dt = variable_list,
	trip_name = trip_name,
	day_name = day_name,
	ids = id_cols,
	wts = wt_cols,
	remove_outliers = remove_outliers,
	threshold = threshold,
	weighted = weighted,
	hts_data = data
	)
	}
	# If a checkbox variable use checkbox for summarize_vartype
	if (variable_list[shared_name == summarize_var, .N] > 1){